Organic light emitting display device and method of manufacturing the same

ABSTRACT

Discussed are an organic light emitting display device and a method of manufacturing the same. The organic light emitting display device according to an embodiment includes a substrate including an active area and a pad area, a thin film transistor (TFT) in the active area of the substrate, an anode electrode on the TFT, an organic emission layer on the anode electrode, a cathode electrode on the organic emission layer, an auxiliary electrode connected to the cathode electrode and disposed on the same layer as the anode electrode, a signal pad in the pad area of the substrate, and a pad electrode connected to the signal pad to cover a top of the signal pad for preventing the top of the signal pad from being corroded. The TFT includes a gate electrode. The signal pad is disposed on the same layer as the gate electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of the Korean PatentApplication No. 10-2015-0076674 filed on May 29, 2015, which is herebyincorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an organic light emitting displaydevice, and more particularly, to a top emission type organic lightemitting display device and a method of manufacturing the same.

Discussion of the Related Art

Organic light emitting display devices are self-emitting devices andhave low power consumption, a fast response time, high emissionefficiency, high luminance, and a wide viewing angle.

The organic light emitting display devices are classified into a topemission type and a bottom emission type, based on a transmissiondirection of light emitted from an organic light emitting device. In thebottom emission type, a circuit element is disposed between an emissionlayer and an image displaying surface, and for this reason, an apertureratio is lowered. On the other hand, in the top emission type, thecircuit element is not disposed between the emission layer and the imagedisplaying surface, and thus, an aperture ratio is enhanced.

FIG. 1 is a schematic cross-sectional view of a related art top emissiontype organic light emitting display device.

As seen in FIG. 1, a thin film transistor (TFT) layer T which includesan active layer 11, a gate insulation layer 12, a gate electrode 13, aninterlayer dielectric 14, a source electrode 15, and a drain electrode16 is formed in an active area AA on a substrate 10, and a passivationlayer 20 and a planarization layer 30 are sequentially formed on the TFTlayer T.

An anode electrode 40 and an auxiliary electrode 50 are formed on theplanarization layer 30. The auxiliary electrode 50 decreases aresistance of a cathode electrode 80 to be described below.

A bank 60 is formed on the anode electrode 40 and the auxiliaryelectrode 50 and defines a pixel area. An organic emission layer 70 isformed in the pixel area defined by the bank 60, and the cathodeelectrode 80 is formed on the organic emission layer 70.

In the top emission type, light emitted from the organic emission layer70 travels through the cathode electrode 80. Therefore, the cathodeelectrode 80 is formed of a transparent conductive material, and forthis reason, a resistance of the cathode electrode 80 increases. Inorder to decrease the resistance of the cathode electrode 80, thecathode electrode 80 is connected to the auxiliary electrode 50.

The gate insulation layer 12 and the interlayer dielectric 14 are formedin a pad area PA on the substrate 10, a signal pad 90 is formed on theinterlayer dielectric 14, and the passivation layer 20 is formed on thesignal pad 90. A hole is formed in the passivation layer 20, and thesignal pad 90 is exposed to the outside through the hole. Since thesignal pad 90 should be connected to an external driving circuit, thehole is formed in the passivation layer 20, and the signal pad 90 isexposed to the outside through the hole.

The related art top emission type organic light emitting display devicehas at least the following problems.

Since the signal pad 90 should be connected to the external drivingcircuit, a top of the signal pad 90 is exposed to the outside. For thisreason, the top of the signal pad 90 is corroded, and the corrosion isspread to another area. In order to prevent the top of the signal pad 90from being corroded, a metal layer which is good in corrosion resistancemay be further formed on the top of the signal pad 90, but in this case,a separate process is additionally performed. Also, in order to preventthe top of the signal pad 90 from being corroded without the separateprocess being additionally performed, an electrode layer which is thesame as the anode electrode 40 may be formed on the signal pad 90through the same process, but in this case, it is unable to preventcorrosion from being made through a side of the electrode layer.

Moreover, in order to connect the signal pad 90 to the external drivingcircuit, the hole is formed in the passivation layer 20, and the top ofthe signal pad 90 is exposed through the hole. However, if the hole ispreviously formed in the passivation layer 20, an etchant for forming apattern of the anode electrode 40 flows in through the hole to damagethe signal pad 90. In order to prevent the damage, the hole of thepassivation layer 20 for exposing the top of the signal pad 90 may beseparately performed after a process of forming the pattern of the anodeelectrode 40 is completed, but in this case, a separate mask process isadditionally performed.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to provide a top emissiontype organic light emitting display device and a method of manufacturingthe same that substantially obviate one or more problems due tolimitations and disadvantages of the related art.

An aspect of the present invention is directed to provide a top emissiontype organic light emitting display device and a method of manufacturingthe same, in which the number of additional processes is minimized, anda signal pad is prevented from being corroded.

In addition to the aforesaid objects of the present invention, otherfeatures and advantages of the present invention will be describedbelow, but will be clearly understood by those skilled in the art fromdescriptions below.

Additional advantages and features of the invention will be set forth inpart in the description which follows and in part will become apparentto those having ordinary skill in the art upon examination of thefollowing or may be learned from practice of the invention. Theobjectives and other advantages of the invention may be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, there isprovided an organic light emitting display device that includes asubstrate including an active area and a pad area, a thin filmtransistor (TFT) in the active area of the substrate, the TFT includinga gate electrode, an anode electrode on the TFT, an organic emissionlayer on the anode electrode, a cathode electrode on the organicemission layer, an auxiliary electrode connected to the cathodeelectrode and disposed on the same layer as the anode electrode, asignal pad in the pad area of the substrate, the signal pad beingdisposed on the same layer as the gate electrode, and a pad electrodeconnected to the signal pad to cover a top of the signal pad forpreventing the top of the signal pad from being corroded.

In another aspect of the present invention, there is provided a methodof manufacturing an organic light emitting display device which includesforming a thin film transistor (TFT) in an active area of a substrateand forming a signal pad and a first pad electrode, connected to thesignal pad, in a pad area of the substrate, forming a passivation layeron the TFT and the first pad electrode, forming a planarization layer onthe passivation layer, removing a certain region of the passivationlayer to simultaneously form an area, through which the TFT is exposedto the outside, and an area through which the first pad electrode isexposed to the outside, forming a first anode electrode connected to theTFT, a first auxiliary electrode spaced apart from the first anodeelectrode, and a second pad electrode that is connected to the first padelectrode and covers the exposed first pad electrode, and forming asecond anode electrode, covering a top and a side surface of the firstanode electrode, and a second auxiliary electrode covering a top and aside surface of the first auxiliary electrode.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a schematic cross-sectional view of a related art organiclight emitting display device;

FIG. 2 is a schematic cross-sectional view of an organic light emittingdisplay device according to an embodiment of the present invention; and

FIGS. 3A to 3J are process cross-sectional views illustrating a methodof manufacturing an organic light emitting display device according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Advantages and features of the present invention, and implementationmethods thereof will be clarified through following embodimentsdescribed with reference to the accompanying drawings. The presentinvention may, however, be embodied in different forms and should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the present invention tothose skilled in the art. Further, the present invention is only definedby scopes of claims.

A shape, a size, a ratio, an angle, and a number disclosed in thedrawings for describing embodiments of the present invention are merelyan example, and thus, the present invention is not limited to theillustrated details. Like reference numerals refer to like elementsthroughout. In the following description, when the detailed descriptionof the relevant known function or configuration is determined tounnecessarily obscure the important point of the present invention, thedetailed description will be omitted. In a case where ‘comprise’,‘have’, and ‘include’ described in the present specification are used,another part may be added unless ‘only˜’ is used. The terms of asingular form may include plural forms unless referred to the contrary.

In construing an element, the element is construed as including an errorrange although there is no explicit description.

In describing a position relationship, for example, when a positionrelation between two parts is described as ‘on˜’, ‘over˜’, ‘under˜’, and‘next˜’, one or more other parts may be disposed between the two partsunless ‘just’ or ‘direct’ is used.

In describing a time relationship, for example, when the temporal orderis described as ‘after˜’, ‘subsequent˜’, ‘next˜’, and ‘before˜’, a casewhich is not continuous may be included unless ‘just’ or ‘direct’ isused.

It will be understood that, although the terms “first”, “second”, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present invention.

Features of various embodiments of the present invention may bepartially or overall coupled to or combined with each other, and may bevariously inter-operated with each other and driven technically as thoseskilled in the art can sufficiently understand. The embodiments of thepresent invention may be carried out independently from each other, ormay be carried out together in co-dependent relationship.

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of an organic light emitting displaydevice 100 according to an embodiment of the present invention. All thecomponents of the organic light emitting display device according to allembodiments of the present invention are operatively coupled andconfigured.

As seen in FIG. 2, the organic light emitting display device 100according to an embodiment of the present invention may include anactive area AA and a pad area PA which are provided on the substrate100.

A thin film transistor (TFT) layer T, a passivation layer 165, aplanarization layer 170, a first anode electrode 180, a second anodeelectrode 200, a first auxiliary electrode 190, a second auxiliaryelectrode 210, a bank 220, a partition wall 230, an organic emissionlayer 240, and a cathode electrode 250 may be formed in the active areaAA on the substrate 100.

The TFT layer T may include an active layer 110, a gate insulation layer120, a gate electrode 130, an interlayer dielectric 140, a sourceelectrode 150, and a drain electrode 160.

The active layer 110 may be formed on the substrate 100 to overlap thegate electrode 130. The active layer 110 may be formed of asilicon-based semiconductor material, or may be formed of an oxide-basedsemiconductor material. A light shielding layer may be further formedbetween the substrate 100 and the active layer 110, and in this case,external light incident through a bottom of the substrate 100 is blockedby the light shielding layer, thereby preventing the active layer 110from being damaged by the external light.

The gate insulation layer 120 may be formed on the active layer 110. Thegate insulation layer 120 may insulate the active layer 110 from thegate electrode 130. The gate insulation layer 120 may be formed of aninorganic insulating material, for example, silicon oxide (SiOx),silicon nitride (SiNx), or a multilayer thereof, but is not limitedthereto. The gate insulation layer 120 may extend to the pad area PA.

The gate electrode 130 may be formed on the gate insulation layer 120.The gate electrode 130 may be formed to overlap the active layer 110with the gate insulation layer 120 therebetween. The gate electrode 130may be formed of a single layer or a multilayer including one ofmolybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti),nickel (Ni), neodymium (Nd), and copper (Cu) or an alloy thereof, but isnot limited thereto.

The gate electrode 130 may include a lower gate electrode 131 and anupper gate electrode 132.

The lower gate electrode 131 may be formed between the gate insulationlayer 120 and the upper gate electrode 132 to enhance an adhesive forcebetween the gate insulation layer 120 and the upper gate electrode 132.Also, the lower gate electrode 131 prevents a bottom of the upper gateelectrode 132 from being corroded. Therefore, an oxidation rate of thelower gate electrode 131 may be lower than that of the upper gateelectrode 132. That is, the lower gate electrode 131 may be formed of amaterial which is stronger in corrosion resistance than a materialincluded in the upper gate electrode 132. As described above, the lowergate electrode 131 may be formed of an alloy (MoTi) of Mo and Ti, but isnot limited thereto.

The upper gate electrode 132 may be formed on a top of the lower gateelectrode 131 and may be formed of copper (Cu), but is not limitedthereto. In order to lower a total resistance of the gate electrode 130,a thickness of the upper gate electrode 132 may be formed thicker thanthat of the lower gate electrode 131.

The interlayer dielectric 140 may be formed on the gate electrode 130.The interlayer dielectric 140 may be formed of the same inorganicinsulating material as that of the gate insulation layer 120, forexample, may be formed of silicon oxide (SiOx), silicon nitride (SiNx),or a multilayer thereof, but is not limited thereto. The interlayerdielectric 140 may extend to the pad area PA.

The source electrode 150 and the drain electrode 160 may be formed toface each other on the interlayer dielectric 140. A first contact holeCH1 exposing one end region of the active layer 110 and a second contacthole CH2 exposing the other end region of the active layer 110 may beincluded in the gate insulation layer 120 and the interlayer dielectric140. The source electrode 150 may be connected to the other end regionof the active layer 110 through the second contact hole CH2, and thedrain electrode 160 may be connected to the one end region of the activelayer 110 through the first contact hole CH1.

The source electrode 150 may include a lower source electrode 151 and anupper source electrode 152.

The lower source electrode 151 may be formed between the interlayerdielectric 140 and the upper source electrode 152 to enhance an adhesiveforce between the interlayer dielectric 140 and the upper sourceelectrode 152. Also, the lower source electrode 151 protects a bottom ofthe upper source electrode 152, thereby preventing the bottom of theupper source electrode 152 from being corroded. Therefore, an oxidationrate of the lower source electrode 151 may be lower than that of theupper source electrode 152. That is, the lower source electrode 151 maybe formed of a material which is stronger in corrosion resistance than amaterial included in the upper source electrode 152. As described above,the lower source electrode 151 may act as an adhesion enhancement layeror an anti-corrosion layer and may be formed of an alloy (MoTi) of Moand Ti, but is not limited thereto.

The upper source electrode 152 may be formed on a top of the lowersource electrode 151. The upper source electrode 152 may be formed of Cuwhich is metal having a low resistance, but is not limited thereto. Theupper source electrode 152 may be formed of metal which is relativelylower in resistance than the lower source electrode 151. In order tolower a total resistance of the source electrode 150, a thickness of theupper source electrode 152 may be formed thicker than that of the lowersource electrode 151.

Similarly to the above-described source electrode 150, the drainelectrode 160 may include a lower drain electrode 161 and an upper drainelectrode 162.

The lower drain electrode 161 may be formed between the interlayerdielectric 140 and the upper drain electrode 162 to enhance an adhesiveforce between the interlayer dielectric 140 and the upper drainelectrode 162 and prevent a bottom of the upper drain electrode 162 frombeing corroded. Therefore, an oxidation rate of the lower drainelectrode 161 may be lower than that of the upper drain electrode 162.That is, the lower drain electrode 161 may be formed of a material whichis stronger in corrosion resistance than a material included in theupper drain electrode 162. As described above, the lower drain electrode161 may be formed of an alloy (MoTi) of Mo and Ti which is the same asthe above-described material of the lower source electrode 151, but isnot limited thereto.

The upper drain electrode 162 may be formed on a top of the lower drainelectrode 161 and may be formed of Cu which is the same as theabove-described material of the upper source electrode 152, but is notlimited thereto. A thickness of the upper drain electrode 162 may beformed thicker than that of the lower drain electrode 161, therebylowering a total resistance of the drain electrode 160.

The upper drain electrode 162 may be formed of the same material as thatof the upper source electrode 152 to have the same thickness as that ofthe upper source electrode 152, and the lower drain electrode 161 may beformed of the same material as that of the lower source electrode 151 tohave the same thickness as that of the lower source electrode 151. Inthis case, the drain electrode 160 and the source electrode 150 may besimultaneously formed through the same process.

A structure of the TFT T is not limited to the illustrated structure,and may be variously modified to structures known to those skilled inthe art. For example, a top gate structure where the gate electrode 130is formed on the active layer 110 is illustrated in the drawing, but theTFT T may be formed in a bottom gate structure where the gate electrode130 is formed under the active layer 110.

The passivation layer 165 may be formed on the TFT layer T, and in moredetail, may be formed on tops of the source electrode 150 and the drainelectrode 160. The passivation layer 165 protects the TFT layer T. Thepassivation layer 165 may be formed of an inorganic insulating material(for example, SiOx and SiNx), but is not limited thereto. Thepassivation layer 165 may extend to the pad area PA.

The planarization layer 170 may be formed on the passivation layer 165.The planarization layer 170 may planarize an upper surface of thesubstrate 100 including the TFT layer T. The planarization layer 170 maybe formed of an organic insulating material such as acryl resin, epoxyresin, phenolic resin, polyamide resin, polyimide resin, or the like,but is not limited thereto. The planarization layer 170 may not extendto the pad area PA.

The first anode electrode 180 and the first auxiliary electrode 190 maybe formed on the planarization layer 170. That is, the first anodeelectrode 180 and the first auxiliary electrode 190 may be formed on thesame layer. A fourth contact hole CH4 exposing the source electrode 150may be included in the passivation layer 165 and the planarization layer170, and the source electrode 150 may be connected to the first anodeelectrode 180 through the fourth contact hole CH4.

The first anode electrode 180 may include a first lower anode electrode181 and a first upper anode electrode 182.

The first lower anode electrode 181 may be formed between theplanarization layer 170 and the first upper anode electrode 182 toenhance an adhesive force between the planarization layer 170 and thefirst upper anode electrode 182. Also, the first lower anode electrode181 protects a bottom of the first upper anode electrode 182, therebypreventing the bottom of the first upper anode electrode 182 from beingcorroded. Therefore, an oxidation rate of the first lower anodeelectrode 181 may be lower than that of the first upper anode electrode182. That is, the first lower anode electrode 181 may be formed of amaterial which is stronger in corrosion resistance than a materialincluded in the first upper anode electrode 182. Also, the first loweranode electrode 181 protects a top of the upper source electrode 152,thereby preventing the top of the upper source electrode 152 from beingcorroded. Therefore, an oxidation rate of the first lower anodeelectrode 181 may be lower than that of the upper source electrode 152.That is, the first lower anode electrode 181 may be formed of a materialwhich is stronger in corrosion resistance than a material included inthe upper source electrode 152. As described above, the first loweranode electrode 181 prevents the top of the upper source electrode 152from being corroded, and thus, the source electrode 150 may be formed inthe above-described two-layer structure. The first lower anode electrode181 may act as an adhesion enhancement layer or an anti-corrosion layerand may be formed of an alloy (MoTi) of Mo and Ti, but is not limitedthereto.

The first upper anode electrode 182 may be formed on a top of the firstlower anode electrode 181. The first upper anode electrode 182 may beformed of Cu which is metal having a low resistance, but is not limitedthereto. The first upper anode electrode 182 may be formed of metalwhich is relatively lower in resistance than the first lower anodeelectrode 181. In order to lower a total resistance of the first anodeelectrode 180, a thickness of the first upper anode electrode 182 may beformed thicker than that of the first lower anode electrode 181.

Similarly to the above-described first anode electrode 180, the firstauxiliary electrode 190 may include a first lower auxiliary electrode191 and a first upper auxiliary electrode 192.

The first lower auxiliary electrode 191 may be formed between theplanarization layer 170 and the first upper auxiliary electrode 192 toenhance an adhesive force between the planarization layer 170 and thefirst upper auxiliary electrode 192 and prevent a bottom of the firstupper auxiliary electrode 192 from being corroded. Therefore, anoxidation rate of the first lower auxiliary electrode 191 may be lowerthan that of the first upper auxiliary electrode 192. That is, the firstlower auxiliary electrode 191 may be formed of a material which isstronger in corrosion resistance than a material included in the firstupper auxiliary electrode 192. As described above, the first lowerauxiliary electrode 191 may be formed of an alloy (MoTi) of Mo and Tiwhich is the same as the above-described material of the first loweranode electrode 181, but is not limited thereto.

The first upper auxiliary electrode 192 may be formed on a top of thefirst lower auxiliary electrode 191 and may be formed of Cu which is thesame as the above-described material of the first upper anode electrode182, but is not limited thereto. A thickness of the first upperauxiliary electrode 192 which is relatively low in resistance may beformed thicker than that of the first lower auxiliary electrode 191which is relatively high in resistance, thereby lowering a totalresistance of the first auxiliary electrode 190.

The first upper auxiliary electrode 192 may be formed of the samematerial as that of the first upper anode electrode 182 to have the samethickness as that of the first upper anode electrode 182, and the firstlower auxiliary electrode 191 may be formed of the same material as thatof the first lower anode electrode 181 to have the same thickness asthat of the first lower anode electrode 181. In this case, the firstauxiliary electrode 190 and the first anode electrode 180 may besimultaneously formed through the same process.

The second anode electrode 200 may be formed on a top of the first anodeelectrode 180. The second anode electrode 200 may be formed to contactthe whole top and a whole side surface of the first anode electrode 180.That is, a separate insulation layer may not be formed between thesecond anode electrode 200 and the first anode electrode 180, and thus,a process of forming an insulation layer and a contact hole may beomitted. The second anode electrode 200 may reflect light, emitted fromthe organic emission layer 240, in an up direction and thus may includea material which is good in reflectivity. Also, the second anodeelectrode 200 may be formed to cover the top and the side surface of thefirst anode electrode 180, thereby preventing the top and the sidesurface of the first anode electrode 180 from being corroded.

The second anode electrode 200 may include a second lower anodeelectrode 201, a second center anode electrode 202, and a second upperanode electrode 203.

The second lower anode electrode 201 may be formed between the firstanode electrode 180 and the second center anode electrode 202. Thesecond lower anode electrode 201 may be formed to cover the top and theside surface of the first anode electrode 180, thereby preventing thefirst anode electrode 180 from being corroded. To this end, an oxidationrate of the second lower anode electrode 201 may be lower than that ofeach of the first lower anode electrode 181 and the first upper anodeelectrode 182 which configure the first anode electrode 180. That is,the second lower anode electrode 201 may be formed of a material whichis stronger in corrosion resistance than a material included in each ofthe first lower anode electrode 181 and the first upper anode electrode182. Also, the second lower anode electrode 201 protects a bottom of thesecond center anode electrode 202, thereby preventing the bottom of thesecond center anode electrode 202 from being corroded. Therefore, anoxidation rate of the second lower anode electrode 201 may be lower thanthat of the second center anode electrode 202. That is, the second loweranode electrode 201 may be formed of a material which is stronger incorrosion resistance than a material included in the second center anodeelectrode 202. The second lower anode electrode 201 may be formed of atransparent conductive material such as indium tin oxide (ITO) or thelike, but is not limited thereto.

The second center anode electrode 202 may be formed between the secondlower anode electrode 201 and the second upper anode electrode 203. Thesecond center anode electrode 202 may be formed of a material which islower in resistance than and better in reflectivity than the secondlower anode electrode 201 and the second upper anode electrode 203, andfor example, may be formed of silver (Ag) and/or the like. However, thepresent embodiment is not limited thereto. A thickness of the secondcenter anode electrode 202 which is relatively low in resistance may beformed thicker than that of each of the second lower anode electrode 201and the second upper anode electrode 203 which are relatively high inresistance, thereby lowering a total resistance of the second anodeelectrode 200.

The second upper anode electrode 203 may be formed on a top of thesecond center anode electrode 202, thereby preventing the top of thesecond center anode electrode 202 from being corroded. To this end, anoxidation rate of the second upper anode electrode 203 may be lower thanthat of the second center anode electrode 202. That is, the second upperanode electrode 203 may be formed of a material which is stronger incorrosion resistance than a material included in the second center anodeelectrode 202. The second upper anode electrode 203 may be formed of atransparent conductive material such as ITO or the like, but is notlimited thereto.

The second auxiliary electrode 210 may be formed on a top of the firstauxiliary electrode 190. The second auxiliary electrode 210 may beformed on the same layer as that of the second anode electrode 200. Thesecond auxiliary electrode 210 may be formed to contact the whole topand a whole side surface of the first auxiliary electrode 190. That is,a separate insulation layer may not be formed between the secondauxiliary electrode 210 and the first auxiliary electrode 190, and thus,a process of forming an insulation layer and a contact hole may beomitted. The second auxiliary electrode 210 may lower a resistance ofthe cathode electrode 250 along with the first auxiliary electrode 190.According to an embodiment of the present invention, in order to lower aresistance of the cathode electrode 250, two auxiliary electrodes (e.g.,the first auxiliary electrode 190 and the second auxiliary electrode210) may be stacked, and thus, the desired resistance characteristics ofthe auxiliary electrodes are more easily adjusted. Also, the secondauxiliary electrode 210 may be formed to cover the top and the sidesurface of the first auxiliary electrode 190, thereby preventing the topand the side surface of the first auxiliary electrode 190 from beingcorroded.

The second auxiliary electrode 210 may include a second lower auxiliaryelectrode 211, a second center auxiliary electrode 212, and a secondupper auxiliary electrode 213.

The second lower auxiliary electrode 211 may be formed between the firstauxiliary electrode 190 and the second center auxiliary electrode 212.The second lower auxiliary electrode 211 may be formed to cover the topand the side surface of the first auxiliary electrode 190, therebypreventing the first auxiliary electrode 190 from being corroded. Tothis end, an oxidation rate of the second lower auxiliary electrode 211may be lower than that of each of the first lower auxiliary electrode191 and the first upper auxiliary electrode 192 which configure thefirst auxiliary electrode 190. That is, the second lower auxiliaryelectrode 211 may be formed of a material which is stronger in corrosionresistance than a material included in each of the first lower auxiliaryelectrode 191 and the first upper auxiliary electrode 192. Also, thesecond lower auxiliary electrode 211 protects a bottom of the secondcenter auxiliary electrode 212, thereby preventing the bottom of thesecond center auxiliary electrode 212 from being corroded. Therefore, anoxidation rate of the second lower auxiliary electrode 211 may be lowerthan that of the second center auxiliary electrode 212. That is, thesecond lower auxiliary electrode 211 may be formed of a material whichis stronger in corrosion resistance than a material included in thesecond center auxiliary electrode 212. The second lower auxiliaryelectrode 211 may be formed of a transparent conductive material such asindium tin oxide (ITO) or the like, but is not limited thereto.

The second center auxiliary electrode 212 may be formed between thesecond lower auxiliary electrode 211 and the second upper auxiliaryelectrode 213. The second center auxiliary electrode 212 may be formedof a material which is lower in resistance than and better inreflectivity than the second lower auxiliary electrode 211 and thesecond upper auxiliary electrode 213, and for example, may be formed ofsilver (Ag) and/or the like. However, the present embodiment is notlimited thereto. A thickness of the second center auxiliary electrode212 which is relatively low in resistance may be formed thicker thanthat of each of the second lower auxiliary electrode 211 and the secondupper auxiliary electrode 213 which are relatively high in resistance,thereby lowering a total resistance of the second auxiliary electrode210.

The second upper auxiliary electrode 213 may be formed on a top of thesecond center auxiliary electrode 212, thereby preventing the top of thesecond center auxiliary electrode 212 from being corroded. To this end,an oxidation rate of the second upper auxiliary electrode 213 may belower than that of the second center auxiliary electrode 212. That is,the second upper auxiliary electrode 213 may be formed of a materialwhich is stronger in corrosion resistance than a material included inthe second center auxiliary electrode 212. The second upper auxiliaryelectrode 213 may be formed of a transparent conductive material such asITO or the like, but is not limited thereto.

The second upper auxiliary electrode 213 may be formed of the samematerial as that of the second upper anode electrode 203 to have thesame thickness as that of the second upper anode electrode 203, thesecond center auxiliary electrode 212 may be formed of the same materialas that of the second center anode electrode 202 to have the samethickness as that of the second center anode electrode 202, and thesecond lower auxiliary electrode 211 may be formed of the same materialas that of the second lower anode electrode 201 to have the samethickness as that of the second lower anode electrode 201. In this case,the second auxiliary electrode 210 and the second anode electrode 200may be simultaneously formed through the same process.

The bank 220 may be formed on the second anode electrode 200 and thesecond auxiliary electrode 210.

The bank 220 may be formed on each of one side and the other side of thesecond anode electrode 200 to expose a top of the second anode electrode200. Since the bank 220 is formed to expose the top of the second anodeelectrode 200, an area where an image is displayed is secured. Also,since the bank 220 is formed on each of the one side and the other sideof the second anode electrode 200, a side surface of the second centeranode electrode 202 vulnerable to corrosion is prevented from beingexposed to the outside, thereby preventing the side surface of thesecond center anode electrode 202 from being corroded.

The bank 220 may be formed on each of one side and the other side of thesecond auxiliary electrode 210 to expose a top of the second auxiliaryelectrode 210. Since the bank 220 is formed to expose the top of thesecond auxiliary electrode 210, an electrical connection space betweenthe second auxiliary electrode 210 and the cathode electrode 250 issecured. Also, since the bank 220 is formed on each of the one side andthe other side of the second auxiliary electrode 210, a side surface ofthe second center auxiliary electrode 212 vulnerable to corrosion isprevented from being exposed to the outside, thereby preventing the sidesurface of the second center auxiliary electrode 212 from beingcorroded.

Moreover, the bank 220 may be formed between the second anode electrode200 and the second auxiliary electrode 210 to insulate the second anodeelectrode 200 from the second auxiliary electrode 210. The bank 220 maybe formed of an organic insulating material such as polyimide resin,acryl resin, benzocyclobutene (BCB), or the like, but is not limitedthereto.

The partition wall 230 may be formed on the second auxiliary electrode210. The partition wall 230 may be spaced apart from the bank 220 by acertain distance, and the second auxiliary electrode 210 may beelectrically connected to the cathode electrode 250 through a separationspace between the partition wall 230 and the bank 220. The secondauxiliary electrode 210 may be electrically connected to the cathodeelectrode 250 without forming the partition wall 230. However, if thepartition wall 230 is formed, the organic emission layer 240 is moreeasily deposition-formed. This will be described below in more detail.

If the partition wall 230 is not formed, a mask pattern which covers atop of the second auxiliary electrode 210 is needed in depositing theorganic emission layer 240, in order for the top of the second auxiliaryelectrode 210 not to be covered by the organic emission layer 240.However, if the partition wall 230 is formed, a top of the partitionwall 230 may act like eaves in depositing the organic emission layer240, and thus, since the organic emission layer 240 is not depositedunder the eaves, the mask pattern which covers the top of the secondauxiliary electrode 210 is not needed. That is, with respect to a casewhere the organic light emitting display device is seen from the frontthereof, when the top of the partition wall 230 that acts as eaves isformed to cover a separation space between the partition wall 230 andthe bank 220, the organic emission layer 240 cannot penetrate into theseparation space between the partition wall 230 and the bank 220, andthus, the second auxiliary electrode 210 may be exposed in theseparation space between the partition wall 230 and the bank 220.Particularly, the organic emission layer 240 may be formed by adeposition process such as an evaporation process which is excellent instraightness of a deposited material, and thus, the organic emissionlayer 240 is not deposited in the separation space between the partitionwall 230 and the bank 220 in a process of depositing the organicemission layer 240.

As described above, a width of the top of the partition wall 230 may beformed greater than that of a bottom of the partition wall 230, in orderfor the top of the partition wall 230 to act as the eaves. The partitionwall 230 may include a lower first partition wall 231 and an uppersecond partition wall 232. The first partition wall 231 may be formed ona top of the second auxiliary electrode 210 and may be formed of thesame material as that of the bank 220 through the same process as thatof the bank 220. The second partition wall 232 may be formed on a top ofthe first partition wall 231. A width of a top of the second partitionwall 232 may be formed greater than that of a bottom of the secondpartition wall 232, and particularly, the top of the second partitionwall 232 may be formed to cover the separation space between thepartition wall 230 and the bank 220 and may act as eaves.

The organic emission layer 240 may be formed on the second anodeelectrode 200. The organic emission layer 240 may include a holeinjection layer, a hole transport layer, an emission layer, an electrontransport layer, and an electron injection layer. The organic emissionlayer 240 may be modified to have various structures known to thoseskilled in the art.

The organic emission layer 240 may extend to the top of the bank 220.However, the organic emission layer 240 may not extend to the top of thesecond auxiliary electrode 210 in a state of covering the top of thesecond auxiliary electrode 210. This is because when the organicemission layer 240 covers the top of the second auxiliary electrode 210,it is difficult to electrically connect the second auxiliary electrode210 to the cathode electrode 250. As described above, the organicemission layer 240 may be formed by a deposition process without a maskthat covers the top of the second auxiliary electrode 210, and in thiscase, the organic emission layer 240 may be formed on the top of thepartition wall 230.

The cathode electrode 250 may be formed on the organic emission layer240. The cathode electrode 250 may be formed on a surface from whichlight is emitted, and thus may be formed of a transparent conductivematerial. Since the cathode electrode 250 is formed of a transparentconductive material, a resistance of the cathode electrode 250 is high,and for this reason, in order to lower the resistance of the cathodeelectrode 250, the cathode electrode 250 may be connected to the secondauxiliary electrode 210. That is, the cathode electrode 250 may beconnected to the second auxiliary electrode 210 through the separationspace between the partition wall 230 and the bank 220. The cathodeelectrode 250 may be formed by a deposition process such as a sputteringprocess which is not good in straightness of a deposited material, andthus, the cathode electrode 250 may be deposited in the separation spacebetween the partition wall 230 and the bank 220 in a process ofdepositing the cathode electrode 250.

An encapsulation layer may be further formed on the cathode electrode250 and prevents penetration of water. The encapsulation layer may usevarious materials known to those skilled in the art. Also, a colorfilter may be further formed for each pixel and on the cathode electrode250, and in this case, white light may be emitted from the organicemission layer 240.

The gate insulation layer 120, the interlayer dielectric 140, a signalpad 300, and a pad electrode 400 may be formed in the pad area PA of thesubstrate 100.

The gate insulation layer 120 may be formed on the substrate 100. Theinterlayer dielectric 140 extend from the active area AA and may beformed all over the pad area PA.

The signal pad 300 may be formed on the gate insulation layer 120. Thesignal pad 300 may be formed on the same layer as that of the gateelectrode 130 disposed in the active area AA.

The signal pad 300 may include a lower signal pad 301 and an uppersignal pad 302.

The lower signal pad 301 may be formed between the gate insulation layer120 and the upper signal pad 302 to enhance an adhesive force betweenthe gate insulation layer 120 and the upper signal pad 302. Also, thelower signal pad 301 prevents a bottom of the upper signal pad 302 frombeing corroded. Therefore, an oxidation rate of the lower signal pad 301may be lower than that of the upper signal pad 302. That is, the lowersignal pad 301 may be formed of a material which is stronger incorrosion resistance than a material included in the upper signal pad302. As described above, the lower signal pad 301 may be formed of analloy (MoTi) of Mo and Ti which is the same as the above-describedmaterial of the lower gate electrode 131, but is not limited thereto.

The upper signal pad 302 may be formed on a top of the lower signal pad301. The upper signal pad 302 may be formed of Cu which is metal havinga low resistance, but is not limited thereto. The upper signal pad 302may be formed of metal which is relatively lower in resistance than thelower signal pad 301. In order to lower a total resistance of the signalpad 300, a thickness of the upper signal pad 302 may be formed thickerthan that of the lower signal pad 301.

The upper signal pad 302 may be formed of the same material as that ofthe upper gate electrode 132 to have the same thickness as that of theupper gate electrode 132, and the lower signal pad 301 may be formed ofthe same material as that of the lower gate electrode 131 to have thesame thickness as that of the lower gate electrode 131. In this case,the signal pad 300 and the gate electrode 130 and/or the drain electrode160 may be simultaneously formed through the same process.

The interlayer dielectric 140 may be formed on the signal pad 300. Theinterlayer dielectric 140 may extend from the active area AA. A thirdcontact hole CH3 exposing a portion of the signal pad 300 may beincluded in the interlayer dielectric 140.

The interlayer dielectric 140 may be formed to expose a top of thesignal pad 300 and cover a side surface of the signal pad 300. Since theinterlayer dielectric 140 is formed to expose the top of the signal pad300, the interlayer dielectric 140 may be connected to thebelow-described pad electrode 400. Also, the interlayer dielectric 140may be formed on each of one side and the other side of the signal pad300, and thus, the side surface of the upper signal pad 302 vulnerableto corrosion is not exposed to the outside, thereby preventing the sidesurface of the upper signal pad 302 from being corroded.

The pad electrode 400 may be formed on the interlayer dielectric 140.The pad electrode 400 may be connected to the signal pad 300 through thethird contact hole CH3. The pad electrode 400 may be exposed to theoutside and connected to an external driver.

The pad electrode 400 may include a lower pad electrode 401, an upperpad electrode 402, and a cover pad electrode 403.

The lower pad electrode 401 may be formed to cover a top of the uppersignal pad 302 through the third contact hole CH3, thereby preventingthe upper signal pad 302 from being corroded. To this end, an oxidationrate of the lower pad electrode 401 may be lower than that of the uppersignal pad 302. That is, the lower pad electrode 401 may be formed of amaterial which is stronger in corrosion resistance than a materialincluded in the upper signal pad 302. As described above, the lower padelectrode 401 prevents the top of the upper signal pad 302 from beingcorroded, and thus, the signal pad 300 may be formed in theabove-described two-layer structure. An oxidation rate of the lower padelectrode 401 may be lower than that of the upper pad electrode 402. Thelower pad electrode 401 may be formed of an alloy (MoTi) of Mo and Tiwhich is the same as the above-described material of the lower sourceelectrode 151 and/or the lower drain electrode 161, but is not limitedthereto. The lower pad electrode 401 may be formed of the same materialas that of the lower source electrode 151 and/or the lower drainelectrode 161 to have the same thickness as that of the lower sourceelectrode 151 and/or the lower drain electrode 161, and in this case,the lower pad electrode 401 and the lower source electrode 151 and/orthe lower drain electrode 161 may be pattern-formed through the samemask process.

The upper pad electrode 402 may be formed between the lower padelectrode 401 and the cover pad electrode 403. The upper pad electrode402 may be formed of Cu which is metal having a low resistance, but isnot limited thereto. The upper pad electrode 402 may be formed of metalwhich is relatively lower in resistance than the lower pad electrode 401and the cover pad electrode 403. In order to lower a total resistance ofthe pad electrode 400, a thickness of the upper pad electrode 402 may beformed thicker than that of each of the lower pad electrode 401 and thecover pad electrode 403. The upper pad electrode 402 may be formed ofthe same material as that of the upper source electrode 152 and/or theupper drain electrode 162 to have the same thickness as that of thefirst upper anode electrode 182 and/or the first upper auxiliaryelectrode 192, and in this case, the upper pad electrode 402 and theupper source electrode 152 and/or the upper drain electrode 162 may bepattern-formed through the same mask process.

The cover pad electrode 403 may be formed on the upper pad electrode402. The cover pad electrode 403 may be formed to cover a top and a sidesurface of the upper pad electrode 402, thereby preventing the upper padelectrode 402 from being corroded. That is, the cover pad electrode 403prevents the upper pad electrode 402 from being exposed to the outside.To this end, an oxidation rate of the cover pad electrode 403 may belower than that of the upper pad electrode 402. That is, the cover padelectrode 403 may be formed of a material which is stronger in corrosionresistance than a material forming the upper pad electrode 402.

The cover pad electrode 403 may cover up to a side surface of the lowerpad electrode 401. In this case, an oxidation rate of the cover padelectrode 403 may be lower than that of the lower pad electrode 401.That is, the cover pad electrode 403 may be formed of a material whichis stronger in corrosion resistance than a material included in thelower pad electrode 401. The cover pad electrode 403 may be formed of analloy (MoTi) of Mo and Ti, but is not limited thereto. The cover padelectrode 403 may be formed of the same material as that of the firstlower anode electrode 181 and/or the first lower auxiliary electrode 191to have the same thickness as that of the first lower anode electrode181 and/or the first lower auxiliary electrode 191, and in this case,the cover pad electrode 403 and the first lower anode electrode 181and/or the first lower auxiliary electrode 191 may be pattern-formedthrough the same mask process.

FIGS. 3A to 3J are process cross-sectional views illustrating a methodof manufacturing an organic light emitting display device according toan embodiment of the present invention and relate to a method ofmanufacturing the above-described organic light emitting display deviceof FIG. 2. Thus, like reference numerals refer to like elements, and ina material and a structure of each element, the same or similardescriptions may not be repeated or may be brief.

First, as seen in FIG. 3A, an active layer 110, a gate insulation layer120, a gate electrode 130, and a signal pad 300 may be sequentiallyformed on a substrate 100.

To provide a more detailed description, the active layer 110 may beformed on the substrate 100, the gate insulation layer 120 may be formedon the active layer 110, the gate electrode 130 may be formed on thegate insulation layer 120, and the signal pad 300 may be formed.

Here, the active layer 110 and the gate electrode 130 may be formed inan active area AA, the gate insulation layer 120 may be formed to extendfrom the active area AA to a pad area PA, and the signal pad 300 may beformed in the pad area AA.

The gate electrode 130 may be configured with a lower gate electrode 131and an upper gate electrode 132, and the signal pad 300 may beconfigured with a lower signal pad 301 and an upper signal pad 302. Thegate electrode 130 and the signal pad 300 may be simultaneously formedof the same material by the same patterning process.

Subsequently, as seen in FIG. 3B, a interlayer dielectric 140 may beformed on the gate electrode 130, and a first contact hole CH1 and asecond contact hole CH2 may be formed in the gate insulation layer 120and the interlayer dielectric 140. Subsequently, a third contact holeCH3 may be in a drain electrode connected to one end region of theactive layer 110 through the first contact hole CH1, a source electrode150 connected to the other end region of the active layer 110 throughthe second contact hole CH2, and the interlayer dielectric 140, and afirst pad electrode 400 a may be formed to be connected to the signalpad 300 through the third contact hole CH3.

Here, the source electrode 150 and the drain electrode 160 may be formedin the active area AA, and the interlayer dielectric 140 may be formedto extend from the active area AA to the pad area PA, and the first padelectrode 400 a may be formed in the pad area PA. Through such aprocess, a TFT layer T may be formed in the active area AA.

The source electrode 150 may include a lower source electrode 151 and anupper source electrode 152, the drain electrode 160 may include a lowerdrain electrode 161 and an upper drain electrode 162, and the first padelectrode 400 a may include a first lower pad electrode 401 and a firstupper pad electrode 402. The source electrode 150, the drain electrode160, and the first pad electrode 400 a may be simultaneously formed ofthe same material through the same patterning process.

Subsequently, as seen in FIG. 3C, a passivation layer 165 may be formedon the source electrode 150, the drain electrode 160, and the first padelectrode 400 a, and a planarization layer 170 may be formed on thepassivation layer 165. The planarization layer 170 may include a fourthcontact hole CH4.

The passivation layer 165 may be formed to extend from the active areaAA to the pad area PA, and the planarization layer 170 may be formed inthe active area AA. Since a TFT is not formed in the pad area PA, thenecessity to planarize a surface thereof is small, and thus, theplanarization layer 170 may not be formed in the pad area PA.

Subsequently, as seen in FIG. 3D, the fourth contact hole CH4 may beformed in the passivation layer 165, and by removing a certain region ofthe passivation layer 165 in the pad area PA, the first pad electrode400 a may be exposed to the outside. The source electrode 150 may beexposed to the outside through the fourth contact hole CH4 included inthe passivation layer 165 and the planarization layer 170.

According to an embodiment of the present invention, a process offorming the fourth contact hole CH4 of the passivation layer 165 forexposing the source electrode 150 to the outside and a process ofremoving a certain region of the passivation layer 165 in the pad areaPA for exposing the first pad electrode 400 a to the outside may besimultaneously performed, and thus, by using one mask process, thefourth contact hole CH4 may be formed and the certain region of thepassivation layer 165 may be removed, whereby the number of maskprocesses does not increase. To provide a more detailed description onthis, since the first upper pad electrode 402 is vulnerable tocorrosion, an etchant should not be brought in contact with the firstupper pad electrode 402. According to an embodiment of the presentinvention, the exposed first upper pad electrode 402 may be covered by asecond pad electrode 400 b in a process of FIG. 3E to be describedbelow, and thus, the etchant cannot be brought in contact with the firstupper pad electrode 402. For the same reason as this, the process offorming the fourth contact hole CH4 and the process of removing thecertain region of the passivation layer 165 may be simultaneouslyperformed.

Subsequently, as seen in FIG. 3E, a first anode electrode 180 and afirst auxiliary electrode 190 may be formed to be spaced apart from eachother on the planarization layer 170 in the active area AA, and thesecond pad electrode 400 b may be formed on the first pad electrode 400a in the pad area PA.

The first anode electrode 180 may be formed to be connected to thesource electrode 150 through the fourth contact hole CH4, and the secondpad electrode 400 b may be formed to cover a top and a side surface ofthe first pad electrode 400 a.

The first anode electrode 180 may be configured with a first lower anodeelectrode 181 and a first upper anode electrode 182. The first auxiliaryelectrode 190 may be configured with a first lower auxiliary electrode191 and a first upper auxiliary electrode 192. The second pad electrode400 b may be configured with a second lower pad electrode 403 and asecond upper pad electrode 404.

The first anode electrode 180, the first auxiliary electrode 190, andthe second pad electrode 400 b may be simultaneously formed of the samematerial through the same patterning process.

Subsequently, as seen in FIG. 3F, a second anode electrode 200 may beformed on the first anode electrode 180 in the active area AA, a secondauxiliary electrode 210 may be formed on the first auxiliary electrode190 in the active area AA, and a third pad electrode 400 c may be formedon the second pad electrode 400 b.

The second anode electrode 200 may be pattern-formed to cover a top anda side surface of the first anode electrode 180, and the secondauxiliary electrode 210 may be pattern-formed to cover a top and a sidesurface of the first auxiliary electrode 190. The third pad electrode400 c may be pattern-formed to cover a top and a side surface of thesecond pad electrode 400 b.

The second anode electrode 200, the second auxiliary electrode 210, andthe third pad electrode 400 c may be simultaneously formed of the samematerial through the same patterning process.

The second anode electrode 200 may include a second lower anodeelectrode 201, a second center anode electrode 202, and a second upperanode electrode 203. The second auxiliary electrode 210 may include asecond lower auxiliary electrode 211, a second center auxiliaryelectrode 212, and a second upper auxiliary electrode 213. The third padelectrode 400 c may include a third lower pad electrode 405, a thirdcenter pad electrode 406, and a third upper pad electrode 407.

Subsequently, as seen in FIG. 3G, a process of pattern-forming thesecond anode electrode 200 and the second auxiliary electrode 210 mayinclude an etching process based on an etchant, and in the etchingprocess, the second upper pad electrode 404 and the third pad electrode400 c which are disposed in the pad area PA may be etched together. Thatis, in a process of pattern-forming the second anode electrode 200 andthe second auxiliary electrode 210, by removing the second upper padelectrode 404 and the third pad electrode 400 c, the pad electrode 400which includes only the first pad electrode 400 a and the second lowerpad electrode 403 may be finished.

A photoresist pattern may be formed on the third pad electrode 400 c,the planarization layer 170, the second anode electrode 200, and thesecond auxiliary electrode 210 through a half-tone mask process, and byashing the photoresist pattern, a process of removing the third padelectrode 400 c and the second upper pad electrode 404 and a process ofpattern-forming the second anode electrode 200 and the second auxiliaryelectrode 210 may be simultaneously performed without performing aprocess illustrated in FIG. 3F. In this case, a photoresist patternformed on the third pad electrode 400 c and the second upper padelectrode 404 may be thin, and a photoresist pattern formed on thesecond anode electrode 200 and the second auxiliary electrode 210 may bethick, whereby the third pad electrode 400 c and the second upper padelectrode 404 may be removed and the second anode electrode 200 and thesecond auxiliary electrode 210 may remain. The process of removing thethird pad electrode 400 c and the second upper pad electrode 404 is notlimited thereto, and various manufacturing methods may be performed.

Subsequently, as seen in FIG. 3H, a bank 220 may be formed on each ofone side and the other side of the second anode electrode 200 to exposea top of the second anode electrode 200, and moreover, the bank 220 maybe formed on each of one side and the other side of the second auxiliaryelectrode 210 to expose a top of the second auxiliary electrode 210

Moreover, a first partition wall 231 and a second partition wall 232 maybe sequentially formed on the exposed top of the second auxiliaryelectrode 210. The first partition wall 231 and the bank 220 may besimultaneously formed of the same material through the same patterningprocess. The partition wall 230 may be disposed to be spaced apart fromthe bank 220 by a certain distance, and thus, a separation space may beprovided between the partition wall 230 and the bank 220.

In order for a top of the partition wall 230 to act as eaves, a width ofa top of the second partition wall 232 may be adjusted to greater thanthat of a bottom of the second partition wall 232. Particularly, withrespect to a case where the organic light emitting display device isseen from the front thereof, the top of the second partition wall 232may cover the separation space between the partition wall 230 and thebank 220, and thus, in a process of depositing an organic emission layer240 to be described below, the organic emission layer 240 cannot bedeposited in the separation space between the partition wall 230 and thebank 220.

Subsequently, as seen in FIG. 3I, the organic emission layer 240 may beformed on the second anode electrode 200. The organic emission layer 240may be formed by a deposition process such as an evaporation processwhich is excellent in straightness of a deposited material, and thus,the organic emission layer 240 is not deposited in the separation spacebetween the partition wall 230 and the bank 220 although the organicemission layer 240 is deposited on the bank 220 and the top of thepartition wall 230. That is, since the top of the partition wall 230 mayact like eaves in depositing the organic emission layer 240, the organicemission layer 240 cannot be deposited in the separation space betweenthe partition wall 230 and the bank 220 even when the organic emissionlayer 240 is deposited without a mask pattern covering the top of thesecond auxiliary electrode 210.

Subsequently, as seen in FIG. 3J, a cathode electrode 250 may be formedon the organic emission layer 240.

The cathode electrode 250 may be formed to be connected to the secondauxiliary electrode 210 through the separation space between thepartition wall 230 and the bank 220. The cathode electrode 250 may beformed by a deposition process such as a sputtering process which is notgood in straightness of a deposited material, and thus, the cathodeelectrode 250 may be deposited in the separation space between thepartition wall 230 and the bank 220 in a process of depositing thecathode electrode 250.

As described above, according to the embodiments of the presentinvention, since the pad electrode is formed to cover the top of thesignal pad, the signal pad is prevented from being corroded.Accordingly, the signal pad may be formed in the two-layer structurewhich includes the lower signal pad and the upper signal pad vulnerableto corrosion.

Moreover, according to the embodiments of the present invention, thecontact hole for externally exposing the source electrode and the areafor externally exposing the pad electrode may be simultaneously formed,and thus, one mask process is not additionally performed.

Moreover, according to the embodiments of the present invention, the twoauxiliary electrodes (for example, the first auxiliary electrode and thesecond auxiliary electrode) may be stacked for lowering a resistance ofthe cathode electrode, and thus, the desired resistance characteristicof the auxiliary electrode is more easily adjusted.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. An organic light emitting display devicecomprising: a substrate including an active area and a pad area; a thinfilm transistor (TFT) in the active area of the substrate, the TFTincluding a gate electrode, a source electrode, and a drain electrode;an insulating layer on the TFT; an anode electrode on the insulatinglayer; an organic emission layer on the anode electrode; a cathodeelectrode on the organic emission layer; an auxiliary electrodeconnected to the cathode electrode and disposed on a same layer as theanode electrode; a signal pad in the pad area of the substrate, thesignal pad being disposed on a same layer as the gate electrode; and apad electrode connected to the signal pad to cover a top of the signalpad for preventing the top of the signal pad from being corroded,wherein the anode electrode comprises a first anode electrode and asecond anode electrode, wherein the first anode electrode includes afirst lower anode electrode in contact with the source electrode or thedrain electrode of the TFT, and a first upper anode electrode on thefirst lower anode electrode, wherein the second anode electrode includesa second lower anode electrode covering a top surface and a side surfaceof the first anode electrode, a second center anode electrode on thesecond lower anode electrode, and a second upper anode electrode on thesecond center anode electrode, and wherein portions of the first loweranode electrode and the second lower anode electrode are coplanar anddirectly contact the insulating layer.
 2. The organic light emittingdisplay device of claim 1, wherein the pad electrode comprises a lowerpad electrode, an upper pad electrode, and a cover pad electrode, andthe cover pad electrode is provided to cover a top and a side surface ofthe upper pad electrode.
 3. The organic light emitting display device ofclaim 2, wherein an oxidation rate of each of the lower pad electrodeand the cover pad electrode is lower than an oxidation rate of the upperpad electrode, and a resistance of the upper pad electrode is lower thana resistance of each of the lower pad electrode and the cover padelectrode.
 4. The organic light emitting display device of claim 2,wherein the source electrode includes a lower source electrode and anupper source electrode, and the lower pad electrode comprises a materialwhich is the same as a material of the lower source electrode, and theupper pad electrode comprises a material which is the same as a materialof the upper source electrode.
 5. The organic light emitting displaydevice of claim 2, wherein the cover pad electrode comprises a materialwhich is the same as a material of the first lower anode electrode. 6.The organic light emitting display device of claim 1, wherein anoxidation rate of each of the second lower anode electrode and thesecond upper anode electrode is lower than an oxidation rate of thesecond center anode electrode, and a resistance of the second centeranode electrode is lower than a resistance of each of the second loweranode electrode and the second upper anode electrode.
 7. The organiclight emitting display device of claim 1, wherein the signal padcomprises a lower signal pad and an upper signal pad on the lower signalpad, an oxidation rate of the lower signal pad is lower than anoxidation rate of the upper signal pad, and a resistance of the uppersignal pad is lower than a resistance of the lower signal pad.
 8. Theorganic light emitting display device of claim 1, wherein the auxiliaryelectrode comprises a first auxiliary electrode and a second auxiliaryelectrode provided to cover a top and a side surface of the firstauxiliary electrode.
 9. The organic light emitting display device ofclaim 8, further comprising: a bank on each of one side and the otherside of the second auxiliary electrode; and a partition wall on thesecond auxiliary electrode, the partition wall being spaced apart fromthe bank, wherein the cathode electrode is connected to the secondauxiliary electrode through a separation space between the bank and thepartition wall.
 10. The organic light emitting display device of claim1, wherein the source electrode includes a lower source electrode and anupper source electrode, and a thickness of the upper source electrode isthicker than that of the lower source electrode.
 11. The organic lightemitting display device of claim 1, wherein a thickness of the firstupper anode electrode is thicker than that of the first lower anodeelectrode.
 12. The organic light emitting display device of claim 8,wherein a thickness of the first upper auxiliary electrode is thickerthan that of the first lower auxiliary electrode.
 13. The organic lightemitting display device of claim 1, wherein a thickness of the secondcenter anode electrode is thicker than that of each of the second loweranode electrode and the second upper anode electrode.
 14. The organiclight emitting display device of claim 8, wherein the second auxiliaryelectrode includes a second lower auxiliary electrode, a second centerauxiliary electrode, and a second upper auxiliary electrode.
 15. Theorganic light emitting display device of claim 1, further comprising: abank on each of one side and the other side of the second anodeelectrode.
 16. The organic light emitting display device of claim 9,wherein a width of a top of the partition wall is greater than that of abottom of the partition wall.
 17. The organic light emitting displaydevice of claim 1, further comprising: an interlayer dielectric on thesignal pad.
 18. The organic light emitting display device of claim 17,wherein the interlayer dielectric is formed to expose a top of thesignal pad and cover a side surface of the signal pad.
 19. The organiclight emitting display device of claim 1, wherein the pad electrodecomprises a lower pad electrode, an upper pad electrode, and a cover padelectrode, and a thickness of the upper pad electrode is thicker thanthat of each of the lower pad electrode and the cover pad electrode. 20.An organic light emitting display device comprising: a substrateincluding an active area and a pad area; a thin film transistor (TFT) inthe active area of the substrate, the TFT including a gate electrode, asource electrode, and a drain electrode; an insulating layer on the TFT;an anode electrode on the insulating layer; an organic emission layer onthe anode electrode; and a cathode electrode on the organic emissionlayer, wherein the anode electrode comprises a first anode electrode anda second anode electrode, wherein the first anode electrode includes afirst lower anode electrode in contact with the source electrode or thedrain electrode of the TFT, and a first upper anode electrode on thefirst lower anode electrode, wherein the second anode electrode includesa second lower anode electrode covering a top surface and a side surfaceof the first anode electrode, a second center anode electrode on thesecond lower anode electrode, and a second upper anode electrode on thesecond center anode electrode, and wherein portions of the first loweranode electrode and the second lower anode electrode are coplanar anddirectly contact the insulating layer.